Biology subjects

Campos, C.

Publications and source records attributed to Campos, C..

5 recordsLinked to original sources

bioRxiv2025

CaMPARI2 Enables Stimulus-Locked Whole-Brain Activity Mapping at Cellular Resolution in Unrestrained Larval Zebrafish

Visualizing active neurons and circuits in vivo is critical for investigating the neural activity that underlies behavior. While several established methodologies are available to achieve this end in larval zebrafish, they are limited by the scale of tissue visualization, temporal resolution, need to restrain larvae, and/or accessibility of necessary instruments. Here, we establish a pipeline for the visualization and quantification of spatiotemporally precise whole-brain neural activity in larval zebrafish using CaMPARI2, a genetically encoded calcium indicator. Using temporally specific photoconverting UV light exposures, we capture whole-brain "snapshots" of neural activity time-locked to stimuli during unrestrained larval behavior. We optimize experimental conditions for establishing sub-second neuronal activity changes across acoustically-evoked behavioral paradigms spanning minutes to hours. We then leverage this system to pinpoint brain-wide neural activity changes during nonassociative habituation learning, observing distinct activity signatures in the subpallium, preoptic area, and habenulae that are altered through pharmacological disruption of habituation learning. This approach effectively complements the temporal precision achievable through post hoc activity detection methods and expands the accessibility of large-scale behavioral circuit dissection beyond highly specialized real-time volumetric imaging equipment.

neuroscience↗

bioRxiv2024

Practice beyond performance stabilization increases the use of online adjustments to unpredictable perturbations in an interceptive task

In recent decades, research has focused on motor adjustments in interception tasks within predictable environments. However, emerging studies suggest that continued practice beyond performance stabilization enhances the ability to adapt to unpredictable events. The objective of this study was to investigate the effects of practicing until performance stabilization versus extended practice through superstabilization on the ability to adjust to unpredictable perturbations in intercepting a moving target. We hypothesized superstabilization would better facilitate motor adjustments in response to unpredictable perturbations. Forty participants engaged in an interception task until they achieved either performance stabilization or superstabilization. Subsequently, both stabilization and superstabilization groups were tested in an unpredictable environment, where, in certain trials, the targets velocity unexpectedly changed after the onset of the movement. The findings revealed that the superstabilization group made more adjustments in response to these perturbations than the stabilization group, attributed to their developed capacity to use online feedback as a control mechanism more efficiently. In contrast, the practice until performance stabilization did not foster this adaptive mechanism. These results support the notion that learning is a dynamic process that extends beyond the point of performance stabilization, emphasizing the benefits of continued practice for mastering complex motor tasks in variable contexts.

neuroscience↗

bioRxiv2024

De novo pyrimidine biosynthesis inhibition synergizes with BCL-XL targeting in pancreatic cancer

Oncogenic KRAS, the genetic driver of 90% of pancreatic adenocarcinoma (PDAC), induces a metabolic rewiring characterized, in part, by dependency on de novo pyrimidine biosynthesis. Pharmacologic inhibition of dihydroorotate dehydrogenase (DHODH), an enzyme in the de novo pyrimidine synthesis pathway, delays pancreatic tumor growth in vivo; however, limited monotherapy efficacy suggests compensatory pathways and that combinatorial strategies are required for enhanced efficacy. Here, we use an integrated metabolomic, quantitative temporal proteomic and in vitro and in vivo DHODH inhibitor anchored CRISPR/Cas9 genetic screening approach to identify compensatory pathways to DHODH inhibition (DHODHi) and targets for combination strategies. We demonstrate that DHODHi alters the apoptotic regulatory proteome thereby enhancing sensitivity to inhibitors of the anti-apoptotic BCL2L1 (BCL-XL) protein. Combinatorial regimens with DHODH and BCL-XL inhibition synergistically induce apoptosis in PDAC cell lines and patient-derived PDAC organoids. In vivo DHODH inhibition with Brequinar and BCL-XL degradation with DT2216, a proteolysis targeting chimera (PROTAC), significantly inhibits the growth of PDAC tumors. Our data defines mechanisms of adaptation to DHODH inhibition and identifies a combination therapy strategy in PDAC.

cancer biology↗

bioRxiv2024

Phylogenomic and genomic analysis reveals unique and shared genetic signatures of Mycobacterium kansasii complex species

Species belonging to the Mycobacterium kansasii complex (MKC) are frequently isolated from humans and the environment and can cause serious diseases. The most common MKC infections are caused by the species M. kansasii (stricto sensu), leading to tuberculosis-like disease. However, a broad spectrum of virulence, antimicrobial resistance and pathogenicity of these non-tuberculous mycobacteria (NTM) are observed across the MKC. Many genomic aspects of the MKC that relate to these broad phenotypes are not well elucidated. Here, we performed genomic analyses from a collection of 665 MKC strains, isolated from environmental, animal and human sources. We inferred the MKC pangenome, mobilome, resistome, virulome and defense systems and show that the MKC species harbors unique and shared genomic signatures. High frequency of presence of prophages and different types of defense systems was observed. We found that the M. kansasii species splits into four lineages, of which three are lowly represented and mainly in Brazil, while one lineage is dominant and globally spread. Moreover, we show that four sub-lineages of this most distributed M. kansasii lineage emerged during the 20th century. Further analysis of the M. kansasii genomes revealed almost 300 regions of difference contributing to genomic diversity, as well as fixed mutations that may explain the M. kansasiis increased virulence and drug resistance. RepositoriesBioProject PRJNA1048499. Impact statementMycobacterium kansasii complex (MKC) is a group of closely related non-tuberculous mycobacteria species, recognized as a significant source of human infection. Species belonging to the MKC may present a broad spectrum of virulence, antimicrobial resistance and pathogenicity and there is a lack of knowledge about their genomic content related to these broad phenotypes. We have provided whole genomic sequencing DNA for 342 MKC isolates and, together with public data, investigated the MKC pangenome, mobilome, resistome, virulome and defense systems and show unique and shared genetic signatures within MKC species. Furthermore, with phylogenomic and bayesian population analysis, we inferred the distribution and emergence of the Mycobacterium kansasii species lineages and sub-lineages. This study has considerably expanded the MKC available data, by providing genomic sequences of isolates from countries and global regions with unknown or poorly MKC data until now. Data summaryNGS data generated in the study are available in the NCBI Sequence Read Archive (SRA) repository under the accession number PRJNA1048499 and the accession numbers for all data sets used are provided in Supplementary Table 1.

evolutionary biology↗

bioRxiv2023

Dual role of Toxoplasma gondii ROP5 and ROP18 for NLRP3 inhibition

Inflammasome activation leads release of IL-1{beta}, a proinflammatory cytokine that drives antimicrobial immune responses. Toxoplasma gondii has been shown to activate the NLRP3 inflammasome but the trigger has not yet been identified. Here we provide evidence that vacuolar disruption is a prerequisite for NLRP3 activation. T. gondii type I ROP5 and ROP18 protect the parasitophorous vacuolar membrane (PVM) and thereby inhibit inflammasome activation and IL-1{beta} release. Besides protection of the PVM, we demonstrate an additional function of ROP5 and ROP18 for NLRP3 inhibition. We demonstrate the molecular mechanism of this inhibition includes direct interaction with GBP5. In conclusion, T. gondii ROP5 and ROP18 inhibit IL-1{beta} production by protection of the intracellular replicative niche of the parasite and by actively subverting NLRP3 activation. Our findings provide further insight into the intricate mechanisms governing inflammasome activation and inhibition, enhancing our understanding of the complex dynamics during T. gondii infection. O_FIG O_LINKSMALLFIG WIDTH=155 HEIGHT=200 SRC="FIGDIR/small/558105v1_ufig1.gif" ALT="Figure 1"> View larger version (78K): org.highwire.dtl.DTLVardef@10a71b2org.highwire.dtl.DTLVardef@ae753eorg.highwire.dtl.DTLVardef@19365e7org.highwire.dtl.DTLVardef@74d9c_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗